These tools from COMP Cams will allow machining of the cylinder head to the proper size for your spring. Each cutter requires the use of an arbor/ pilot, which is available in three different sizes. These arbors/pilots will also work with the valve guide cutters used for shortening the guide for a high lift cam or installing a COMP Cams PTFE seal for oil control. * Seat cutters available in many sizes from 1.320"-1.810" O.D. * Valve guide cutters available to cut guide to .446", .494",.500", .530" or .625" * A rbors/pilots available for 5/16", 11/32" and 3/8" diameters PartNumber : cca4732 Description : 11/32" Arbor/Pilot for Seat & Guide Cutters Title : 4732 11/32 Arbor, (for Cutters) California Proposition 65 : WARNING: This product contains a chemical known to the State of California to cause cancer, birth defects or other reproductive harm. Valve Diameter : 11/32 Fabrication::Tools